A large number of functionally active chemicals are known for use with personal care and beauty products, hygiene products, health-care related products, and skin-contacting products. For example, such actives include antimicrobial or antibacterial agents, antioxidant agents, antiseptic-type agents skin repairing agents, and fragrances. Unfortunately, many of these functionally active chemicals are not stable under various environmental conditions. For example, if such actives include volatile components, such as those found in fragrances they may dissipate into the surrounding environment upon exposure to air and humidity conditions. Therefore such chemicals may demonstrate short shelf lives when in use, and present serious packaging/storage concerns. As a result, costly packaging requirements may be necessary for products incorporating such chemicals. This instability therefore creates a significant limitation on the wide adoption of the potentially useful chemistry, and limits the long-term efficacy of products incorporating such chemistry. Further, processing challenges such as elevated temperatures may exist, and as a result, may present a need to limit exposure to environmental stimuli during manufacture.
Additional challenges that use of such active chemicals presents include the difficulties involved with gradually controlling the release of such active chemicals, as well as the potential side effects/costs resulting from use of chemically degraded products. Other actives, such as antioxidants, are also often not stable when exposed to ambient conditions, such as the air of a user's pantry or storage closets. Antioxidants can readily be oxidized by oxygen in the air. Some skin repairing chemicals are also not stable when exposed to the surrounding environment. For example, the skin repairing agent retinol is not stable under ambient conditions without protection from the environment. In fact, it can become a skin irritant when its concentration is relatively high. A need therefore exists for a versatile composition that effectively stabilizes functional chemical actives, and releases such actives upon demand at a desirable rate and profile.
Certainly, attempts have been made to overcome the stability and storage limitations presented by such actives. For example, attempts have been suggested for stabilizing retinol by encapsulating it in pH sensitive polymers and then releasing it at a later time by changing the solubility of the encapsulating matrix through a pH change. The encapsulated retinol still suffers significant degradation, presumably from oxidation. Others have suggested in order to overcome such stability issues, to convert retinol into an ester as a proactive (a precursor to the retinol active) and then at a later time, to convert the ester into the active form by use of enzymes present in a user's body after delivery through a user's skin. However, with such methodology, only a small portion of the ester is used effectively by the skin layer and a majority of the esters are wasted by the system. Such a system may also actually lead to side effects when too much retinol ester is used to achieve effective dosages on the skin. Therefore, a need still exists for delivery compositions for skin repair actives.
In connection with the delivery of fragrances (such as in connect on with personal care absorbent products), it has been suggested to encapsulate fragrances in polymeric matrices for stabilization and delivery benefits. However, even with such encapsulation technology, there is a further need for fragrance encapsulation technology for use in consumer products which offers effective protection for such volatiles as well as a controlled release. Existing encapsulation chemistries for consumer products often leak or release prematurely. Therefore a continuing need exists for a material composition that both provides stability for unstable actives, and which also provides for release of actives in a controlled manner.